Advances in Science and Technology Vol. 133

Abstract: Tactile sensors in wearable devices have gained attention for their potential applications in enhancing amenability, generation, and functionality for the human body, including sensing and control. This study elaborates on the design of a tactile sensor consisting of EeonTex conductive stretchable elastic fibre, which possesses a bi-directionally stretchable elastic fibre, and was formulated by coating nylon/spandex with a long-lasting conductive formulation. This fabric has proven to be beneficial for use in various different e-tactile applications. The authors systematically investigated the performance of the tactile sensor via 2 different manipulative gestures on a part of the upper limb of two different subjects. The tactile sensor was observed to change its electrical resistance when mechanical force was applied to its surface. It was also noted to be lightweight, inexpensive, stretchable, flexible, and easy to design and set up. This type of tactile sensor possesses the ability to recognise the intention of muscle movement and measure the muscle activities from the forearm. The prime objective of this study was to use such sensors as sleeves mounted on the forearms of the upper limbs. The reasoning behind this was that when muscle contract, they change their shape which in turn results in mechanical pressure being applied to the sensor. Experimental results showed that the tactile sensor’s feedback successfully detected open/closed hands when the sensor sleeve was worn on the forearm region.

Abstract: The construction industry generates a significant amount of waste, posing challenges for efficient waste management and resource recovery. This paper presents a preliminary study on the use of lightweight computer vision (CV) algorithms for the automatic recognition of construction and demolition waste (CDW) materials. Utilizing image datasets acquired by drones, the study aims to develop strategies for distinguishing between individual CDW materials based on the mean intensity gradient, brightness, and relative representation of color channels. Results indicate that the proposed method can effectively recognize crucial CDW materials, paving the way for potential applications in industry and geodesy. Further research is needed to test additional materials and metrics to refine the method for practical implementation.

Abstract: Polyvinylidene Fluoride (PVDF) and Lead Zirconate Titanate (PZT) thin-film sensors can be used to detect acoustic emissions, and their low thickness (28µm PVDF sensors available) allow them to be embedded (positioned within a laminate). However, the characteristics and sensitivity of these sensors within composite structures require further study. The attenuation curves of PZT, silver ink metallised PVDF and gold metallised PVDF sensors, when mounted using a variety of couplants such as ultrasonic gel, resin, silicone adhesive and thin double-sided adhesive tape, have been generated. Investigations also include positioning the sensor within the laminate, as opposed to on the surface, and monitoring the performance changes with respect to the through-thickness position. The sensors coupled using resin have shown to generally have the highest amplitude, with the highest being the PZT yielding 88 dB at 5cm. Initial comparisons of signal detection by the sensors with respect to fibre orientation have shown that signal travelling along the fibres generally has higher amplitude when compared to at 45^o. This research is the first step toward identifying the preferred sensor type and position within the structure for damage detection.

Abstract: Nowadays, the demand for glass fibre-reinforced polymers (GFRPs) has increased in the industry owing to their low weight, high strength, corrosion resistance and low cost compared with other fibre-reinforced polymer composites. However, GFRP is anisotropic material with low interlaminar strength where the damage can occur without warning. Integrating a real-time damage detection process can mitigate this problem. Therefore, this paper presents the initial fabrication of an embedded capacitive sensor into the GFRP by using conductive electrodes inbetween its layers. To form the sensing electrodes, glass fibre yarns were coated with conductive material and braided into the fibregalss woven fabric. Two coating methods were considered to form embedded electrodes in this work which include aerosol spray coatings that were carbon based and gold-based physical vapour deposition, (PVD). It has been shown that spray coating has a weak bond and the carbon particles disperse during the molding process. In the PVD technique the nanoparticle (Au) distributed uniformly along the fibres and has a good resistance (≈100Ω). The capacitive sensor based on gold coating was exaimined using a three point bending test which demonstrate linear response toward the flexural load with a sensitivity of 25.1 fF/N.

Abstract: The study of water condensation phenomena is important in order to evaluate the performance of materials and coatings employed in the fabrication of waste heat recovery units including heat exchangers, heat pipes, condensing economizers and related functional surfaces. Fast evaluation of lab-scale samples is important during research and development of coatings for wetting phenomena under controlled, reproducible, and stable humidity and temperature conditions of both sample and environment. To study these effects, we report on the construction of a lab-scale condensation chamber, along with its evaluation and benchmarking with superhydrophobic coatings on stainless steel using perfluorooctyl silane (PFOTS). A working unit has been successfully fabricated and applied in a highly responsive device capable of recording the condensation performance of flat specimens under controlled conditions. Sample temperature was maintained with 0.10 °C deviation. The humidity response time of the chamber is 17.2 s per degree of RH% while the maximum relative humidity variation is +/- 3.2%RH. The unit successfully delivered valuable data over hydrophillic, hydrophobic and superhydrophobic surfaces. Data useful for studying open research issues such the relationship of contact angle and condensation phenomena.

Abstract: Li-ion batteries (LIB) are one of the most prevalent kinds of batteries used in electronic devices to store electrical energy due to their steady voltage, high energy density, and excellent cycle performance. However, its quick charging and discharging cycle generates a lot of heat which may reduce battery capacity and destroy the electrode material's nanostructure and crystal structure. As a result, a scientific and efficient battery thermal management system (BTMS) is crucial. In this paper, we suggested a BTMS for a 9-cell battery pack with cell spacing of 9mm. Air-cooled and PCM-based systems were simulated using COMSOL Multiphysics 6.0 and compared against a bare-cell battery pack where a temperature drop of 3.53 K and 5.04 K was observed respectively after incorporating the cooling system. In our final study, we simulated a hybrid BTMS that used both forced air cooling and PCM and compared it to a scenario where air cooling was the only type of cooling used by the system. This produced interesting results as the temperature in the hybrid system increased by 1.48 K. Therefore, in order for the hybrid system to benefit from both cooling systems, an in-depth evaluation of the fan's air flow properties, as well as the PCM thickness and material, must take place. The thickness and material must be such that the air cooling provided by the flow control mechanism reaches the actual electrochemical cell.

Abstract: In the framework of the iWAYS project, a synergy between energy and water reclamation and exploitation is addressed by means of the development and the installation of a wide array of technologies in three different industrial sectors: ceramic tile manufacturing, aluminium fluoride production and steel tubes manufacturer. The aim of the project is the creation of customized and integrated systems to achieve a substantial reduction in the thermal waste and in the freshwater consumption; this is the principal challenge the iWAYS project is solving by developing a set of technologies capable of recovering water and energy from challenging exhaust streams for productive use in the industrial processes. iWAYS systems will then treat steam condensate to meet the water quality requirements of each industrial process, while the recovered heat will be used to reduce primary energy consumption. iWAYS will recover additional materials from flue gas such as valuable acids or particulates, improving the production’s raw material efficiency and reducing detrimental emissions to the environment. The iWAYS technology will provide a reduction in the freshwater consumption greater that the 30% in each industrial case; with regards to the energy recovery, iWAYS will recover 6 GWh/y in the ceramic sector, more than 5 GWh/y in the chemical scenario and approximately 1 GWh/y in the steel sector. The iWAYS solution will have a payback lower than 5 years.

Abstract: Construction and demolition waste (CDW) accounted for almost 36% of total waste produced in the European Union in 2018. Growing recovery rates are achieved but mainly for low-value applications. Variable composition and characteristics undermine customers’ confidence who prefers primary materials with certified properties and at more competitive value/cost. Zero energy and waste targets are driving to rethink the waste value chain, necessitating a search for new technologies to reduce carbon emissions and waste volumes towards a more efficient and circular system. This paper presents an outline of the approaches to enhance CDW management that will be developed in the newly funded Horizon Europe project RECONMATIC. This project will develop digital and automated solutions to support advanced CDW management towards zero targets and will explore applications of technologies at different phases of the asset whole life cycle. Technical issues will be considered in aspects such as material segregation, pre-demolition audits, selective deconstruction, waste traceability procedures, as well as broader economical-societal issues such as business model, health & safety, sustainability, and technology readiness level. RECONMATIC aims to usher a paradigm change in CDW management by helping the construction industry taking a step change in circular economy development.

Abstract: Nowadays’ sustainability-driven systems require a product to be environmentally beneficial as well as cost-effective whilst maintaining its great performance. In these circumstances, the pavement industry has emphasized its concern over waste production, reduced materials costs and conserving resources. Henhce, the seeking for new engineering solutions to move toward more sustainable, eco-friendly, and economically beneficial management. In this context, the use of RA (Reclaimed Asphalt) in the new asphalt mixtures has generated well-defined environmental benefits especially in terms of the reduction in raw-material consumption and possibility to upcycle the waste derived from existing old pavements. This study aims to evaluate the efficiency of the addition of selected rejuvenators which help to restore some of the properties of aged bituminous binder in RA, crumb rubber and plastic (LDPE) waste on the performance of asphalt mixture designed with elevated RA content (50 %). Mechanical performance was evaluated by means of laboratory investigations for typical characteristics dedicated to durability, stiffness and cracking potential. The results showed that a proper dosage of a suitable type of rejuvenation agent as well as the crumb rubber and plastic waste can enhance the overall durability of the elevated RA content asphalt mixtures.